The current paradigm, despite the successes of the excellent theories that construct it, quantum mechanics included, is facing many obstacles. Many principles remain unproven, attributes of elementary particles cannot be derived and calculated, and mysteries are un-resolved. This situation results from the lack of a deeper underlying theoretical layer that explores the geometrodynamics of space. Our " GeometroDynamic Model of reality " , the GDM, presented here, is this required layer. The GDM reveals the essence of charge, elementary particles, gravitation, and inertia. It also relates to additional fundamental subjects. The GDM provides derivations and accurate calculations of the radii and masses of elementary particles. Its specificities enable us to suggest new experiments of validation or falsification. Some of these subjects have already been addressed in our recently published papers, " On the Essence of Electric Charge " , [1], [2], " On the Essence of Gravitation and Inertia " , [3], [4], " Where is Anti-Matter? " [5] and " The Photon and the Quantum Enigma " [6].